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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Copyright (C) 2011 The Guava Authors<a name="line.2"></a>
<span class="sourceLineNo">003</span> *<a name="line.3"></a>
<span class="sourceLineNo">004</span> * Licensed under the Apache License, Version 2.0 (the "License");<a name="line.4"></a>
<span class="sourceLineNo">005</span> * you may not use this file except in compliance with the License.<a name="line.5"></a>
<span class="sourceLineNo">006</span> * You may obtain a copy of the License at<a name="line.6"></a>
<span class="sourceLineNo">007</span> *<a name="line.7"></a>
<span class="sourceLineNo">008</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.8"></a>
<span class="sourceLineNo">009</span> *<a name="line.9"></a>
<span class="sourceLineNo">010</span> * Unless required by applicable law or agreed to in writing, software<a name="line.10"></a>
<span class="sourceLineNo">011</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.11"></a>
<span class="sourceLineNo">012</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.12"></a>
<span class="sourceLineNo">013</span> * See the License for the specific language governing permissions and<a name="line.13"></a>
<span class="sourceLineNo">014</span> * limitations under the License.<a name="line.14"></a>
<span class="sourceLineNo">015</span> */<a name="line.15"></a>
<span class="sourceLineNo">016</span><a name="line.16"></a>
<span class="sourceLineNo">017</span>package com.google.common.util.concurrent;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>import com.google.common.annotations.Beta;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import com.google.common.base.Preconditions;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import com.google.common.base.Throwables;<a name="line.21"></a>
<span class="sourceLineNo">022</span><a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.util.concurrent.Callable;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.util.concurrent.Executor;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import java.util.concurrent.Executors;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import java.util.concurrent.Future;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import java.util.concurrent.ScheduledExecutorService;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import java.util.concurrent.ThreadFactory;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import java.util.concurrent.TimeUnit;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import java.util.concurrent.locks.ReentrantLock;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import java.util.logging.Level;<a name="line.31"></a>
<span class="sourceLineNo">032</span>import java.util.logging.Logger;<a name="line.32"></a>
<span class="sourceLineNo">033</span><a name="line.33"></a>
<span class="sourceLineNo">034</span>import javax.annotation.concurrent.GuardedBy;<a name="line.34"></a>
<span class="sourceLineNo">035</span><a name="line.35"></a>
<span class="sourceLineNo">036</span>/**<a name="line.36"></a>
<span class="sourceLineNo">037</span> * Base class for services that can implement {@link #startUp} and {@link #shutDown} but while in<a name="line.37"></a>
<span class="sourceLineNo">038</span> * the "running" state need to perform a periodic task.  Subclasses can implement {@link #startUp},<a name="line.38"></a>
<span class="sourceLineNo">039</span> * {@link #shutDown} and also a {@link #runOneIteration} method that will be executed periodically.<a name="line.39"></a>
<span class="sourceLineNo">040</span> *<a name="line.40"></a>
<span class="sourceLineNo">041</span> * &lt;p&gt;This class uses the {@link ScheduledExecutorService} returned from {@link #executor} to run<a name="line.41"></a>
<span class="sourceLineNo">042</span> * the {@link #startUp} and {@link #shutDown} methods and also uses that service to schedule the<a name="line.42"></a>
<span class="sourceLineNo">043</span> * {@link #runOneIteration} that will be executed periodically as specified by its<a name="line.43"></a>
<span class="sourceLineNo">044</span> * {@link Scheduler}. When this service is asked to stop via {@link #stop} or {@link #stopAndWait},<a name="line.44"></a>
<span class="sourceLineNo">045</span> * it will cancel the periodic task (but not interrupt it) and wait for it to stop before running<a name="line.45"></a>
<span class="sourceLineNo">046</span> * the {@link #shutDown} method.<a name="line.46"></a>
<span class="sourceLineNo">047</span> *<a name="line.47"></a>
<span class="sourceLineNo">048</span> * &lt;p&gt;Subclasses are guaranteed that the life cycle methods ({@link #runOneIteration}, {@link<a name="line.48"></a>
<span class="sourceLineNo">049</span> * #startUp} and {@link #shutDown}) will never run concurrently. Notably, if any execution of {@link<a name="line.49"></a>
<span class="sourceLineNo">050</span> * #runOneIteration} takes longer than its schedule defines, then subsequent executions may start<a name="line.50"></a>
<span class="sourceLineNo">051</span> * late.  Also, all life cycle methods are executed with a lock held, so subclasses can safely<a name="line.51"></a>
<span class="sourceLineNo">052</span> * modify shared state without additional synchronization necessary for visibility to later<a name="line.52"></a>
<span class="sourceLineNo">053</span> * executions of the life cycle methods.<a name="line.53"></a>
<span class="sourceLineNo">054</span> *<a name="line.54"></a>
<span class="sourceLineNo">055</span> * &lt;h3&gt;Usage Example&lt;/h3&gt;<a name="line.55"></a>
<span class="sourceLineNo">056</span> *<a name="line.56"></a>
<span class="sourceLineNo">057</span> * Here is a sketch of a service which crawls a website and uses the scheduling capabilities to<a name="line.57"></a>
<span class="sourceLineNo">058</span> * rate limit itself. &lt;pre&gt; {@code<a name="line.58"></a>
<span class="sourceLineNo">059</span> * class CrawlingService extends AbstractScheduledService {<a name="line.59"></a>
<span class="sourceLineNo">060</span> *   private Set&lt;Uri&gt; visited;<a name="line.60"></a>
<span class="sourceLineNo">061</span> *   private Queue&lt;Uri&gt; toCrawl;<a name="line.61"></a>
<span class="sourceLineNo">062</span> *   protected void startUp() throws Exception {<a name="line.62"></a>
<span class="sourceLineNo">063</span> *     toCrawl = readStartingUris();<a name="line.63"></a>
<span class="sourceLineNo">064</span> *   }<a name="line.64"></a>
<span class="sourceLineNo">065</span> *<a name="line.65"></a>
<span class="sourceLineNo">066</span> *   protected void runOneIteration() throws Exception {<a name="line.66"></a>
<span class="sourceLineNo">067</span> *     Uri uri = toCrawl.remove();<a name="line.67"></a>
<span class="sourceLineNo">068</span> *     Collection&lt;Uri&gt; newUris = crawl(uri);<a name="line.68"></a>
<span class="sourceLineNo">069</span> *     visited.add(uri);<a name="line.69"></a>
<span class="sourceLineNo">070</span> *     for (Uri newUri : newUris) {<a name="line.70"></a>
<span class="sourceLineNo">071</span> *       if (!visited.contains(newUri)) { toCrawl.add(newUri); }<a name="line.71"></a>
<span class="sourceLineNo">072</span> *     }<a name="line.72"></a>
<span class="sourceLineNo">073</span> *   }<a name="line.73"></a>
<span class="sourceLineNo">074</span> *<a name="line.74"></a>
<span class="sourceLineNo">075</span> *   protected void shutDown() throws Exception {<a name="line.75"></a>
<span class="sourceLineNo">076</span> *     saveUris(toCrawl);<a name="line.76"></a>
<span class="sourceLineNo">077</span> *   }<a name="line.77"></a>
<span class="sourceLineNo">078</span> *<a name="line.78"></a>
<span class="sourceLineNo">079</span> *   protected Scheduler scheduler() {<a name="line.79"></a>
<span class="sourceLineNo">080</span> *     return Scheduler.newFixedRateSchedule(0, 1, TimeUnit.SECONDS);<a name="line.80"></a>
<span class="sourceLineNo">081</span> *   }<a name="line.81"></a>
<span class="sourceLineNo">082</span> * }}&lt;/pre&gt;<a name="line.82"></a>
<span class="sourceLineNo">083</span> *<a name="line.83"></a>
<span class="sourceLineNo">084</span> * This class uses the life cycle methods to read in a list of starting URIs and save the set of<a name="line.84"></a>
<span class="sourceLineNo">085</span> * outstanding URIs when shutting down.  Also, it takes advantage of the scheduling functionality to<a name="line.85"></a>
<span class="sourceLineNo">086</span> * rate limit the number of queries we perform.<a name="line.86"></a>
<span class="sourceLineNo">087</span> *<a name="line.87"></a>
<span class="sourceLineNo">088</span> * @author Luke Sandberg<a name="line.88"></a>
<span class="sourceLineNo">089</span> * @since 11.0<a name="line.89"></a>
<span class="sourceLineNo">090</span> */<a name="line.90"></a>
<span class="sourceLineNo">091</span>@Beta<a name="line.91"></a>
<span class="sourceLineNo">092</span>public abstract class AbstractScheduledService implements Service {<a name="line.92"></a>
<span class="sourceLineNo">093</span>  private static final Logger logger = Logger.getLogger(AbstractScheduledService.class.getName());<a name="line.93"></a>
<span class="sourceLineNo">094</span><a name="line.94"></a>
<span class="sourceLineNo">095</span>  /**<a name="line.95"></a>
<span class="sourceLineNo">096</span>   * A scheduler defines the policy for how the {@link AbstractScheduledService} should run its<a name="line.96"></a>
<span class="sourceLineNo">097</span>   * task.<a name="line.97"></a>
<span class="sourceLineNo">098</span>   *<a name="line.98"></a>
<span class="sourceLineNo">099</span>   * &lt;p&gt;Consider using the {@link #newFixedDelaySchedule} and {@link #newFixedRateSchedule} factory<a name="line.99"></a>
<span class="sourceLineNo">100</span>   * methods, these provide {@link Scheduler} instances for the common use case of running the<a name="line.100"></a>
<span class="sourceLineNo">101</span>   * service with a fixed schedule.  If more flexibility is needed then consider subclassing<a name="line.101"></a>
<span class="sourceLineNo">102</span>   * {@link CustomScheduler}.<a name="line.102"></a>
<span class="sourceLineNo">103</span>   *<a name="line.103"></a>
<span class="sourceLineNo">104</span>   * @author Luke Sandberg<a name="line.104"></a>
<span class="sourceLineNo">105</span>   * @since 11.0<a name="line.105"></a>
<span class="sourceLineNo">106</span>   */<a name="line.106"></a>
<span class="sourceLineNo">107</span>  public abstract static class Scheduler {<a name="line.107"></a>
<span class="sourceLineNo">108</span>    /**<a name="line.108"></a>
<span class="sourceLineNo">109</span>     * Returns a {@link Scheduler} that schedules the task using the<a name="line.109"></a>
<span class="sourceLineNo">110</span>     * {@link ScheduledExecutorService#scheduleWithFixedDelay} method.<a name="line.110"></a>
<span class="sourceLineNo">111</span>     *<a name="line.111"></a>
<span class="sourceLineNo">112</span>     * @param initialDelay the time to delay first execution<a name="line.112"></a>
<span class="sourceLineNo">113</span>     * @param delay the delay between the termination of one execution and the commencement of the<a name="line.113"></a>
<span class="sourceLineNo">114</span>     *        next<a name="line.114"></a>
<span class="sourceLineNo">115</span>     * @param unit the time unit of the initialDelay and delay parameters<a name="line.115"></a>
<span class="sourceLineNo">116</span>     */<a name="line.116"></a>
<span class="sourceLineNo">117</span>    public static Scheduler newFixedDelaySchedule(final long initialDelay, final long delay,<a name="line.117"></a>
<span class="sourceLineNo">118</span>        final TimeUnit unit) {<a name="line.118"></a>
<span class="sourceLineNo">119</span>      return new Scheduler() {<a name="line.119"></a>
<span class="sourceLineNo">120</span>        @Override<a name="line.120"></a>
<span class="sourceLineNo">121</span>        public Future&lt;?&gt; schedule(AbstractService service, ScheduledExecutorService executor,<a name="line.121"></a>
<span class="sourceLineNo">122</span>            Runnable task) {<a name="line.122"></a>
<span class="sourceLineNo">123</span>          return executor.scheduleWithFixedDelay(task, initialDelay, delay, unit);<a name="line.123"></a>
<span class="sourceLineNo">124</span>        }<a name="line.124"></a>
<span class="sourceLineNo">125</span>      };<a name="line.125"></a>
<span class="sourceLineNo">126</span>    }<a name="line.126"></a>
<span class="sourceLineNo">127</span><a name="line.127"></a>
<span class="sourceLineNo">128</span>    /**<a name="line.128"></a>
<span class="sourceLineNo">129</span>     * Returns a {@link Scheduler} that schedules the task using the<a name="line.129"></a>
<span class="sourceLineNo">130</span>     * {@link ScheduledExecutorService#scheduleAtFixedRate} method.<a name="line.130"></a>
<span class="sourceLineNo">131</span>     *<a name="line.131"></a>
<span class="sourceLineNo">132</span>     * @param initialDelay the time to delay first execution<a name="line.132"></a>
<span class="sourceLineNo">133</span>     * @param period the period between successive executions of the task<a name="line.133"></a>
<span class="sourceLineNo">134</span>     * @param unit the time unit of the initialDelay and period parameters<a name="line.134"></a>
<span class="sourceLineNo">135</span>     */<a name="line.135"></a>
<span class="sourceLineNo">136</span>    public static Scheduler newFixedRateSchedule(final long initialDelay, final long period,<a name="line.136"></a>
<span class="sourceLineNo">137</span>        final TimeUnit unit) {<a name="line.137"></a>
<span class="sourceLineNo">138</span>      return new Scheduler() {<a name="line.138"></a>
<span class="sourceLineNo">139</span>        @Override<a name="line.139"></a>
<span class="sourceLineNo">140</span>        public Future&lt;?&gt; schedule(AbstractService service, ScheduledExecutorService executor,<a name="line.140"></a>
<span class="sourceLineNo">141</span>            Runnable task) {<a name="line.141"></a>
<span class="sourceLineNo">142</span>          return executor.scheduleAtFixedRate(task, initialDelay, period, unit);<a name="line.142"></a>
<span class="sourceLineNo">143</span>        }<a name="line.143"></a>
<span class="sourceLineNo">144</span>      };<a name="line.144"></a>
<span class="sourceLineNo">145</span>    }<a name="line.145"></a>
<span class="sourceLineNo">146</span><a name="line.146"></a>
<span class="sourceLineNo">147</span>    /** Schedules the task to run on the provided executor on behalf of the service.  */<a name="line.147"></a>
<span class="sourceLineNo">148</span>    abstract Future&lt;?&gt; schedule(AbstractService service, ScheduledExecutorService executor,<a name="line.148"></a>
<span class="sourceLineNo">149</span>        Runnable runnable);<a name="line.149"></a>
<span class="sourceLineNo">150</span><a name="line.150"></a>
<span class="sourceLineNo">151</span>    private Scheduler() {}<a name="line.151"></a>
<span class="sourceLineNo">152</span>  }<a name="line.152"></a>
<span class="sourceLineNo">153</span><a name="line.153"></a>
<span class="sourceLineNo">154</span>  /* use AbstractService for state management */<a name="line.154"></a>
<span class="sourceLineNo">155</span>  private final AbstractService delegate = new AbstractService() {<a name="line.155"></a>
<span class="sourceLineNo">156</span><a name="line.156"></a>
<span class="sourceLineNo">157</span>    // A handle to the running task so that we can stop it when a shutdown has been requested.<a name="line.157"></a>
<span class="sourceLineNo">158</span>    // These two fields are volatile because their values will be accessed from multiple threads.<a name="line.158"></a>
<span class="sourceLineNo">159</span>    private volatile Future&lt;?&gt; runningTask;<a name="line.159"></a>
<span class="sourceLineNo">160</span>    private volatile ScheduledExecutorService executorService;<a name="line.160"></a>
<span class="sourceLineNo">161</span><a name="line.161"></a>
<span class="sourceLineNo">162</span>    // This lock protects the task so we can ensure that none of the template methods (startUp,<a name="line.162"></a>
<span class="sourceLineNo">163</span>    // shutDown or runOneIteration) run concurrently with one another.<a name="line.163"></a>
<span class="sourceLineNo">164</span>    private final ReentrantLock lock = new ReentrantLock();<a name="line.164"></a>
<span class="sourceLineNo">165</span><a name="line.165"></a>
<span class="sourceLineNo">166</span>    private final Runnable task = new Runnable() {<a name="line.166"></a>
<span class="sourceLineNo">167</span>      @Override public void run() {<a name="line.167"></a>
<span class="sourceLineNo">168</span>        lock.lock();<a name="line.168"></a>
<span class="sourceLineNo">169</span>        try {<a name="line.169"></a>
<span class="sourceLineNo">170</span>          AbstractScheduledService.this.runOneIteration();<a name="line.170"></a>
<span class="sourceLineNo">171</span>        } catch (Throwable t) {<a name="line.171"></a>
<span class="sourceLineNo">172</span>          try {<a name="line.172"></a>
<span class="sourceLineNo">173</span>            shutDown();<a name="line.173"></a>
<span class="sourceLineNo">174</span>          } catch (Exception ignored) {<a name="line.174"></a>
<span class="sourceLineNo">175</span>            logger.log(Level.WARNING,<a name="line.175"></a>
<span class="sourceLineNo">176</span>                "Error while attempting to shut down the service after failure.", ignored);<a name="line.176"></a>
<span class="sourceLineNo">177</span>          }<a name="line.177"></a>
<span class="sourceLineNo">178</span>          notifyFailed(t);<a name="line.178"></a>
<span class="sourceLineNo">179</span>          throw Throwables.propagate(t);<a name="line.179"></a>
<span class="sourceLineNo">180</span>        } finally {<a name="line.180"></a>
<span class="sourceLineNo">181</span>          lock.unlock();<a name="line.181"></a>
<span class="sourceLineNo">182</span>        }<a name="line.182"></a>
<span class="sourceLineNo">183</span>      }<a name="line.183"></a>
<span class="sourceLineNo">184</span>    };<a name="line.184"></a>
<span class="sourceLineNo">185</span><a name="line.185"></a>
<span class="sourceLineNo">186</span>    @Override protected final void doStart() {<a name="line.186"></a>
<span class="sourceLineNo">187</span>      executorService = executor();<a name="line.187"></a>
<span class="sourceLineNo">188</span>      executorService.execute(new Runnable() {<a name="line.188"></a>
<span class="sourceLineNo">189</span>        @Override public void run() {<a name="line.189"></a>
<span class="sourceLineNo">190</span>          lock.lock();<a name="line.190"></a>
<span class="sourceLineNo">191</span>          try {<a name="line.191"></a>
<span class="sourceLineNo">192</span>            startUp();<a name="line.192"></a>
<span class="sourceLineNo">193</span>            runningTask = scheduler().schedule(delegate, executorService, task);<a name="line.193"></a>
<span class="sourceLineNo">194</span>            notifyStarted();<a name="line.194"></a>
<span class="sourceLineNo">195</span>          } catch (Throwable t) {<a name="line.195"></a>
<span class="sourceLineNo">196</span>            notifyFailed(t);<a name="line.196"></a>
<span class="sourceLineNo">197</span>            throw Throwables.propagate(t);<a name="line.197"></a>
<span class="sourceLineNo">198</span>          } finally {<a name="line.198"></a>
<span class="sourceLineNo">199</span>            lock.unlock();<a name="line.199"></a>
<span class="sourceLineNo">200</span>          }<a name="line.200"></a>
<span class="sourceLineNo">201</span>        }<a name="line.201"></a>
<span class="sourceLineNo">202</span>      });<a name="line.202"></a>
<span class="sourceLineNo">203</span>    }<a name="line.203"></a>
<span class="sourceLineNo">204</span><a name="line.204"></a>
<span class="sourceLineNo">205</span>    @Override protected final void doStop() {<a name="line.205"></a>
<span class="sourceLineNo">206</span>      runningTask.cancel(false);<a name="line.206"></a>
<span class="sourceLineNo">207</span>      executorService.execute(new Runnable() {<a name="line.207"></a>
<span class="sourceLineNo">208</span>        @Override public void run() {<a name="line.208"></a>
<span class="sourceLineNo">209</span>          try {<a name="line.209"></a>
<span class="sourceLineNo">210</span>            lock.lock();<a name="line.210"></a>
<span class="sourceLineNo">211</span>            try {<a name="line.211"></a>
<span class="sourceLineNo">212</span>              if (state() != State.STOPPING) {<a name="line.212"></a>
<span class="sourceLineNo">213</span>                // This means that the state has changed since we were scheduled.  This implies that<a name="line.213"></a>
<span class="sourceLineNo">214</span>                // an execution of runOneIteration has thrown an exception and we have transitioned<a name="line.214"></a>
<span class="sourceLineNo">215</span>                // to a failed state, also this means that shutDown has already been called, so we<a name="line.215"></a>
<span class="sourceLineNo">216</span>                // do not want to call it again.<a name="line.216"></a>
<span class="sourceLineNo">217</span>                return;<a name="line.217"></a>
<span class="sourceLineNo">218</span>              }<a name="line.218"></a>
<span class="sourceLineNo">219</span>              shutDown();<a name="line.219"></a>
<span class="sourceLineNo">220</span>            } finally {<a name="line.220"></a>
<span class="sourceLineNo">221</span>              lock.unlock();<a name="line.221"></a>
<span class="sourceLineNo">222</span>            }<a name="line.222"></a>
<span class="sourceLineNo">223</span>            notifyStopped();<a name="line.223"></a>
<span class="sourceLineNo">224</span>          } catch (Throwable t) {<a name="line.224"></a>
<span class="sourceLineNo">225</span>            notifyFailed(t);<a name="line.225"></a>
<span class="sourceLineNo">226</span>            throw Throwables.propagate(t);<a name="line.226"></a>
<span class="sourceLineNo">227</span>          }<a name="line.227"></a>
<span class="sourceLineNo">228</span>        }<a name="line.228"></a>
<span class="sourceLineNo">229</span>      });<a name="line.229"></a>
<span class="sourceLineNo">230</span>    }<a name="line.230"></a>
<span class="sourceLineNo">231</span>  };<a name="line.231"></a>
<span class="sourceLineNo">232</span><a name="line.232"></a>
<span class="sourceLineNo">233</span>  /** Constructor for use by subclasses. */<a name="line.233"></a>
<span class="sourceLineNo">234</span>  protected AbstractScheduledService() {}<a name="line.234"></a>
<span class="sourceLineNo">235</span><a name="line.235"></a>
<span class="sourceLineNo">236</span>  /**<a name="line.236"></a>
<span class="sourceLineNo">237</span>   * Run one iteration of the scheduled task. If any invocation of this method throws an exception,<a name="line.237"></a>
<span class="sourceLineNo">238</span>   * the service will transition to the {@link Service.State#FAILED} state and this method will no<a name="line.238"></a>
<span class="sourceLineNo">239</span>   * longer be called.<a name="line.239"></a>
<span class="sourceLineNo">240</span>   */<a name="line.240"></a>
<span class="sourceLineNo">241</span>  protected abstract void runOneIteration() throws Exception;<a name="line.241"></a>
<span class="sourceLineNo">242</span><a name="line.242"></a>
<span class="sourceLineNo">243</span>  /**<a name="line.243"></a>
<span class="sourceLineNo">244</span>   * Start the service.<a name="line.244"></a>
<span class="sourceLineNo">245</span>   *<a name="line.245"></a>
<span class="sourceLineNo">246</span>   * &lt;p&gt;By default this method does nothing.<a name="line.246"></a>
<span class="sourceLineNo">247</span>   */<a name="line.247"></a>
<span class="sourceLineNo">248</span>  protected void startUp() throws Exception {}<a name="line.248"></a>
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<span class="sourceLineNo">250</span>  /**<a name="line.250"></a>
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<span class="sourceLineNo">280</span>        new ThreadFactory() {<a name="line.280"></a>
<span class="sourceLineNo">281</span>          @Override public Thread newThread(Runnable runnable) {<a name="line.281"></a>
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<span class="sourceLineNo">285</span>    // Add a listener to shutdown the executor after the service is stopped.  This ensures that the<a name="line.285"></a>
<span class="sourceLineNo">286</span>    // JVM shutdown will not be prevented from exiting after this service has stopped or failed.<a name="line.286"></a>
<span class="sourceLineNo">287</span>    // Technically this listener is added after start() was called so it is a little gross, but it<a name="line.287"></a>
<span class="sourceLineNo">288</span>    // is called within doStart() so we know that the service cannot terminate or fail concurrently<a name="line.288"></a>
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<span class="sourceLineNo">292</span>      @Override public void running() {}<a name="line.292"></a>
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<span class="sourceLineNo">304</span>   * Returns the name of this service. {@link AbstractScheduledService} may include the name in<a name="line.304"></a>
<span class="sourceLineNo">305</span>   * debugging output.<a name="line.305"></a>
<span class="sourceLineNo">306</span>   *<a name="line.306"></a>
<span class="sourceLineNo">307</span>   * @since 14.0<a name="line.307"></a>
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<span class="sourceLineNo">317</span>  // We override instead of using ForwardingService so that these can be final.<a name="line.317"></a>
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<span class="sourceLineNo">350</span>   * been cancelled, the {@link #getNextSchedule} method will be called.<a name="line.350"></a>
<span class="sourceLineNo">351</span>   *<a name="line.351"></a>
<span class="sourceLineNo">352</span>   * @author Luke Sandberg<a name="line.352"></a>
<span class="sourceLineNo">353</span>   * @since 11.0<a name="line.353"></a>
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<span class="sourceLineNo">359</span>     * A callable class that can reschedule itself using a {@link CustomScheduler}.<a name="line.359"></a>
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<span class="sourceLineNo">363</span>      /** The underlying task. */<a name="line.363"></a>
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<span class="sourceLineNo">370</span>       * The service that is managing this callable.  This is used so that failure can be<a name="line.370"></a>
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<span class="sourceLineNo">376</span>       * This lock is used to ensure safe and correct cancellation, it ensures that a new task is<a name="line.376"></a>
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<span class="sourceLineNo">378</span>       * ensure that it is assigned atomically with being scheduled.<a name="line.378"></a>
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<span class="sourceLineNo">383</span>      @GuardedBy("lock")<a name="line.383"></a>
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<span class="sourceLineNo">394</span>      public Void call() throws Exception {<a name="line.394"></a>
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<span class="sourceLineNo">406</span>        // to currentFuture doesn't race with itself so that currentFuture is assigned in the<a name="line.406"></a>
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<span class="sourceLineNo">479</span>     * on the same thread as the previous execution of {@link<a name="line.479"></a>
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<span class="sourceLineNo">486</span>}<a name="line.486"></a>




























































</pre>
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